const makeMap = ( attrStr, expectsLowerCase ) => {
  const attrs = attrStr.split( ',' );
  const map = Object.create( null );
  attrs.forEach( t => map[t] = true );
  return expectsLowerCase ?
    val => map[val.toLowerCase()] :
    val => map[val];
};

// 参考https://github.com/vuejs/vue/blob/v2.6.10/src/platforms/web/server/util.js
const isAttr = makeMap(
  'accept,accept-charset,accesskey,action,align,alt,async,autocomplete,'
  + 'autofocus,autoplay,autosave,bgcolor,border,buffered,challenge,charset,'
  + 'checked,cite,class,code,codebase,color,cols,colspan,content,http-equiv,'
  + 'name,contenteditable,contextmenu,controls,coords,data,datetime,default,'
  + 'defer,dir,dirname,disabled,download,draggable,dropzone,enctype,method,for,'
  + 'form,formaction,headers,height,hidden,high,href,hreflang,http-equiv,'
  + 'icon,id,ismap,itemprop,keytype,kind,label,lang,language,list,loop,low,'
  + 'manifest,max,maxlength,media,method,GET,POST,min,multiple,email,file,'
  + 'muted,name,novalidate,open,optimum,pattern,ping,placeholder,poster,'
  + 'preload,radiogroup,readonly,rel,required,reversed,rows,rowspan,sandbox,'
  + 'scope,scoped,seamless,selected,shape,size,type,text,password,sizes,span,'
  + 'spellcheck,src,srcdoc,srclang,srcset,start,step,style,summary,tabindex,'
  + 'target,title,type,usemap,value,width,wrap'
);

function vModel ( self, dataObject, value ) {
  dataObject.props.value = value;
  dataObject.on.input = val => {
    self.$emit( 'input', val );
  };
  // 因为有些组件的v-model绑定的事件是change 所以这里也得监听
  dataObject.on.change = val => {
    self.$emit( 'input', val );
  };
}

const componentChild = {
  'el-input': {
    prepend ( h, conf, key ) {
      return <template slot="prepend">{conf[key]}</template>;
    },
    append ( h, conf, key ) {
      return <template slot="append">{conf[key]}</template>;
    }
  },
  'el-select': {
    options ( h, conf, key ) {
      const list = [];
      conf.options.forEach( item => {
        list.push( <el-option label={item.label} value={item.value} disabled={item.disabled}></el-option> );
      } );
      return list;
    }
  },
  'el-radio-group': {
    options ( h, conf, key ) {
      const list = [];
      conf.options.forEach( item => {
        if ( conf.optionType === 'button' ) list.push( <el-radio-button label={item.value}>{item.label}</el-radio-button> );
        else list.push( <el-radio label={item.value} border={conf.border}>{item.label}</el-radio> );
      } );
      return list;
    }
  },
  'el-checkbox-group': {
    options ( h, conf, key ) {
      const list = [];
      conf.options.forEach( item => {
        if ( conf.optionType === 'button' ) {
          list.push( <el-checkbox-button label={item.value}>{item.label}</el-checkbox-button> );
        } else {
          list.push( <el-checkbox label={item.value} border={conf.border}>{item.label}</el-checkbox> );
        }
      } );
      return list;
    }
  },
  'el-upload': {
    'list-type': ( h, conf, key ) => {
      const list = [];
      if ( conf['list-type'] === 'picture-card' ) {
        list.push( <i class="el-icon-plus"></i> );
      } else {
        list.push( <el-button size="small" type="primary" icon="el-icon-upload">{conf.buttonText}</el-button> );
      }
      if ( conf.showTip ) {
        list.push( <div slot="tip" class="el-upload__tip">只能上传不超过 {conf.fileSize}{conf.sizeUnit} 的{conf.accept}文件</div> );
      }
      return list;
    }
  }
};

export default {
  create(){

  },
  render ( h ) {
    const confClone = JSON.parse( JSON.stringify( this.conf ) );
    const dataObject = {
      attrs: {},
      props: {
        formData: this.formData,
        value: this.value || confClone['defaultValue']
      },
      on: {},
      style: {}
    };
    const children = [];

    const childObjs = componentChild[confClone.tag];
    if ( childObjs ) {
      Object.keys( childObjs ).forEach( key => {
        const childFunc = childObjs[key];
        if ( confClone[key] ) {
          children.push( childFunc( h, confClone, key ) );
        }
      } );
    }

    Object.keys( confClone ).forEach( key => {
      const val = confClone[key];
      if ( key === 'vModel' ) {
        vModel( this, dataObject, this.value === undefined ? confClone['defaultValue'] : this.value );
      } else if ( dataObject[key] ) {
        dataObject[key] = val;
      } else if ( !isAttr( key ) ) {
        dataObject.props[key] = val;
      } else {
        dataObject.attrs[key] = val;
      }
    } );
    return h( this.conf.tag, dataObject, children );
  },
  props: ['conf', 'value', 'formData']
};